Modern passenger, recreation, and work vehicles, such as passenger cars, trucks, tractors, etc., generally include a powertrain with a powerplant, such as an internal combustion engine and/or an electric motor, a transmission, such as a multi-speed automatically-shiftable or automatic transmission, and a differential or final drive. An automatic multi-speed transmission increases the overall operating range of the vehicle by permitting the engine to operate through its torque range multiple times without requiring an operator of the vehicle to manually select specific speed-ratios or gear ranges in a forward or drive mode. Such powertrains typically also provide a reverse mode permitting the powerplant to move the vehicle in a direction opposite to the drive mode, and a park mode which operates to block vehicle movement.
Modern powertrains are typically controlled by specifically programmed electronic controllers. Thus programmed, the controller generally uses data provided by sensors from various vehicle systems to, for example, deliver fuel and air and time the spark in the internal combustion engine, and determine how and when to change gears in the transmission for optimum vehicle performance, fuel economy, and shift quality. Although such a controller is generally programmed to automatically control the powertrain in the drive mode, selection between drive, reverse, and park modes is typically reserved for the vehicle operator.